Spatial distribution of laser beam spreading in turbid tissue-like media containing ingredients

Abstract

The spatial parameters of scattered light in turbid media with different degrees of turbidity and at various depths are studied in this work. The measurements are made at two wavelengths (687 nm and 850 nm). A collimated laser radiation is used in the experiments in order to avoid the effect of input laser beam structure on the measured optical fields. The radial and in depth distribution is measured of the intensity of the forward-scattered optical beam radiation in turbid (tissue-like) media. The influence of small ingredients within the turbid media is also analyzed. The optical properties of the ingredients are different from those of the surrounding turbid medium. Milk-water mixtures are used as a test medium. The intensity distribution within milk solutions with concentrations ranging from 3.3% to 16.5% is measured in depth of more than 10 cm. The experimental results indicate that the presence of small ingredients within the phantom leads to characteristic changes of the intensity distribution. These preliminary results are evaluated as promising for developing a novel technique for determination of optical characteristics of small embedded ingredients in turbid media.